Testing is not a formality. In fact, it's better and easier than ever. Tell your agents to develop your code-base with Red-Green-Refactor Test-driven development. Write failing tests first and run them, then write the code to make the tests pass, then refactor the code as needed. I used to hate writing tests before, but now that I can offload that (and the development, honestly) to AI, it's nothing to keep up with it. Your codebase quality will increase with TDD, because it will reduce the number of things that inadvertently break during updates. Things will break loudly and can be easily fixed (again, by AI) before shipping. If something does manage to get through, add more tests to cover it for next time.

This actually makes the LLMs better at coding as well. They can verify their own results and iterate with far less manual validation.

Yeah, that only works if they follow the plan (they don't), actually write the tests first (they don't) and don't silently defer anything which doesn't have a test written as "speculative without a use case".

Or just write tests to match the buggy code after you call them out for not writing tests.

I mean, the struggle is real...

No matter how weasel-proof you make the plans they are much better weasels and just do as little as possible and "the test not written is the test which never fails." There's a certain amount of zen to them.

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